Process of preparing synthetic drying oils



Patented Nov. 7, 1950 PROCESS OF PREPARING SYNTHETIC DRYING OILS John 0. Zimmer, Union, and Jeffrey H. Bartlett,

Westfield, N. J., assi gnors to Standard Oil Development Company, a corporation of Delaware No Drawing. Application August 20, 1947, Serial No. 769,770

. 7 Claims. 1

This invention relates to drying compositions and related materials and also to a process for preparing such materials. More specifically, it relates to the preparation from petroleum derivatives of a new'type of drying compositions which are suitable for use in paints, varnishes, printing inks, and the like. The materials prepared according to this invention are useful also for other and related purposes. For example, these products may be employed as modifiers for plastics, for natural and synthetic rubber, in caulking compounds, adhesives, factices, and other analogous materials.

In the prior art various proposals have been made for the use of unsaturated materials derived from petroleum as substitutes for the relatively costly drying oils, such as linseed oil, tung oil, and the like, which have long been used in paint, varnish, linoleum, and other products. Generally speaking, however, these petroleum derivatives have not been entirely satisfactory although they have been used to a considerable extent. Among the petroleum derivatives which have been proposed for use as drying oils and the like are some of the oleflnic and diolefinic polymers, for example those having a molecular weight range between 200 and 1000. Various studies conducted in recent years have indicated that gasoline produced by steam cracking of gas oil, etc., has an increased tendency toward gum formation due apparently to a relatively high content of dienes and particularly of coniugated diolefins, It was found that by treating such gasolines in the vapor phase with fresh clay a product of satisfactory gum stability could be obtained, or at least a gasoline which could be satisfactorily stabilized by the use of a small quantity of known antioxidant. As a by-product of this process there resulted a polymer of high iodine number and high diene number which appeared to have promise for use as a drying oil.

As indicated above polymers of high diene content were suggested for use in paints, varnishes, etc., to replace tung oil, linseed oil, and the like, but in use it was found that these polymers tend to dry or polymerize excessively and therefore to become hard, brittle, non-flexible resins. When applied in coating compositions these resinous materials become so hard and brittle that they readily chip, crack, craze, or otherwise become broken in texture and they separate to an objectibnable degree from surfaces which are subject to flexing as in the case of coated sheet metals, linoleums, and the like. As a result of these characteristics, paints and other protective compositions employing particular resins have been found to have poor weather qualities and their resistance to abrasion has been found to be unsatisfactory.

We have discovered, however, that resins of the general type just described, for example those polymers having a molecular weight between 200 and about 1000, such as are obtained by the clay treatment of gasolines high in diolefln content, may be further treated to improve their properties for use as drying oils. Such resins may be reacted with certain organic acids or acidogenic compounds and thereafter esterified with a suitable alcohol to produce a drying oil of superior quality. Resins produced and modified in this manner are suitable not only for use in paints and coating compositions generally but may be used also in adhesives, plastics, caulking compounds, and in various other products where linseed oil and tung oil and the like have been used in the past. They are suitable for use in linoleum, pressboard, plywood, oilcloth, and other materials where flexibility becomes an important consideration.

It is therefore an important object of our invention to modify oleflnic and dioleflnic polymers of the general character described above to substantially improve their normally hard and brittle characteristics 50 that upon drying they will produce tough, flexible films and compositions. A further object of our corporate into oleflnic and dioleflnic polymers derived from petroleum certain constituents containing carboxyl groups to improve the properti s referred to abov.

Specifically, we ,hate found that polymers derived by the clay \tit' itment of hydrocarbons as described above may be suitably modified for our purposes by reacting gig em with alpha-beta unsaturated acids or a ydrides, or with other alpha-beta unsaturat d acidogenic materials. Thus petroleum resins if the character described above may be reacted, ith nitrilesbvhich will yield acids on hydrolysis one example of such a nitrile being acrylonitrii Oleflnic and diolefinic polymers may be reacted with acrylic acid, methacrylic acid, maleic acid, sorbic acid, citraconic acid, itaconic acid, and the like. The corresponding anhydrides, especially maleic anhydride and chlormaleic anhydride are considered particularly suitable.

It is known that maleic anhydrides will react" w th conjugated diolefins according to the Diels- Alder reaction. Maleic anhydrides will also react with monooleflns to yield substituted succinic anhydrides, these products having been described in the prior art.

In U. S. Patent No. 2,342,113, to Blair, there is shown the use of the latter reaction with unsaturated acids, for example. It appears that other acids and anhydrides are useful, particularly those having alpha-beta unsaturation.

As a specific example of oun invention, a petroleum fraction such as gas oil or heavy naphtha, is cracked at a relatively low pressure such as 10 to 50, for example, 30 pounds per square inch gage, at a temperature in the range 1200 invention is to into 1350 F., for example 1250 F., in the presence of a substantial amount of steam, for example 75 mol per cent steam based on the oil feed. The products from the steam cracking operation are subjected to clay treatment in vapor and/or liquid phase and at a temterification may be carried out atvarious tem-' perature of at least 250 to as'much as 500 F. peratures but a temperature range of 100 to From this treatment there results a polymer oil 200 6., preferably about 160 C. (320 F.) is prewhich, as suggested above, has a molecular weight ferred. Secondary mono-hydroxy alcohols are or 200 to about 1000. In this process the total also suitable,-for example 2-ethylhexy1 alcohol. steam cracked hydrocarbon may be treated or As regards polyhydroxy alcohols, the C2 and C3 only various fractions thereof as may be desired. glycols and gly ar a l for u e in the At present, however, we prefer to use the fraction e t rifica ion Step. Th resulting ester is a yboiling below 430 F. The unsaturated hydroing or polymerizable oil having the superior propcarbons boiling below about 100 F. are particurti s referred to hereinabove. larly valuable for other chemical processes and h a h h d r e f fl l ty v wh u y therefore it is preferred to subject the fraction dried, go adhesion, 5 d Wea he ng qualities boiling between about 100 and 430 F. to the and good moisture resistance. clay treatment. is free of brittleness, is not subject to discolora- The products of the clay treatment, it will be tion. does not crack or craze, a d is P e y understood, include both low boiling and high highly s a t t s ap greases. au a ids boilin fractions. Some saturated hydrocarbons and the like. are included in the low boiling fraction for these As a specific illustrative example of the invenare carried along without entering into the polytion a 1700 g. portion of a petroleum resin polymerization reaction. In general, the low boiling mer 0f the yp cr b d above was blown with fraction, that is the fraction which is not polyd y itrogen at 130 to 140 C. to remove any merized or partially polymerized and which boils moisture that might e P ent. up to about 430 F., is removed and used for gasoanhydride was then added and the mixture was line. Gasoline 50 produced is quite free from maintained at a temperature of 175 to 180 C. for tendency toward gum formation. If desired, a app y 6 hours w th t n The resmall amount of the conventional gum inhibitor Sillting Product a then pp u der reduced may be used to further improve this quality. pressure (185 C. at 23 mm.) to remove the un- The fraction boiling above 430 F. is the po1 reacted maleic anhydride and the more volatile mer oil mentioned above which is the starting constituents of the prod O ly a trace of material for the preparation of our improved maleic hydride and about 64 grams of light product. This product appears to consist of polye ds Were distilled over. mers and copolymers of monond diolefins of number of the residual alkylated maleic anhyboth cyclic and non-cyclic structure. Polymers dride was 83. or allqlates of aromatic compounds with olefins A Portion of the above anhydride (1296 g.) was and/or diolefins of cyclic and non-cyclic charact e e fied with 65 g. of gly in the p ter may be present also. The polymer so 13 0- ence of 10 g. of toluene sulfonic acid as a catalyst. duced have the following typical properties: The esterification was carried out by stirring the reaction mixture for 12 hours at 160 C. under. q f AP! 30 mm. pressure. zi ig $23,, 2 esterification was distilled off during the course iscosl y a of the reaction. The finished ester was a hard D1898 No 207'; Solid at room temperature. Iqdlpe mer the anhydride, and the final ester roduct l i i t OF 420 were evaluated for resistance to moisture conggg bollmg p0 n 538 densation and flexing. 50% solutions by weight 40 595 were made by dissolving each of the three materials respectively in a hydrocarbon solvent of Polymers produced as above are next reacted the paint and varnish thinner type (Varsol). with an unsaturated acid, acid anhydride or The solutions thus prepared were applied to acidogenic material as described above. Spepolished steel plates 2" x 4" x by dipping cifically, the polymer may be reacted with maleic and the films were allowed to dry 24 hours at anhydride to form directly a carboxylated prodroom temperature. uct. jected to conditions of 100 F. temperature and The carboxylated product obtained as described humidity (heavy moisture condensation) above is next esterified with a suitable alcohol for '72 hours. and this esterification is an important aspect of appearance of the coatings was noted. the present invention. Either a monoor a Similarly coated panels, after drying, were inpolyhydroxy alcohol may be used for this purpose. serted in a vise and bent through an angle of The mono-hydroxy alcohols may have chain 65 to determine resistance oi the coating to fracture lengths in the C2-C2o range, and may be primary alcohols such as those derived by the hydrogenation or cocoanut oil acids, or from the addition of olefins as in the 0x0 process. It is not necessary that the alcohols be separated into narrow fractions, and mixtures of alcohols, for example, Cm-Cm inclusive, may be employed. Es-

A good drying oil It dries hard but 168 g. of maleic The saponification The water resulting from the The original poly- These panels were then sub- At the end of the test period the caused by flexing. The results are tabulated below.

Table I Anhydride Polymer-Maleic An- Petroleum Resin Polymer hydride Condensate Gllvirsutaerll ne Humidity Cabinet-72 hours Coatingvery white. Large amounts Coating white. Some No discoloraru rust. tion or rust. 120 Flexing Severe film fracture Some film fracture.... Nto film tracure.

The above data indicate that esterification of the petroleum resin-maleic anhydride condensation product very considerably improves its usefulness as a component of protective coatings. The product appears to be especially useful as a replacement for drying oil in paints and varnishes.

It will be understood that although catalysts may be employed, and a specific catalyst was used in the esterification step in the foregoing example, the reactions in general may not require a catalyst. The reaction temperature should be above 100 C. (212 F.) and obviously may be varied. The temperature range is usually below about 250 C. (482 F.) the range of about 140 to about 200 C. bein preferred for condensation of the resin with maleic anhydride and generally similar temperature ranges for reaction with other acids and nitriles. The temperature for esterification likewise may vary, depending upon the materials used and the catalyst, if any. In general, as indicated above, esterificatlon is carried out at a somewhat elevated temperature, for example 100 to 200 C., and preferably at reduced pressure.

Our unsaturated polymers, derived from petroleum hydrocarbons, may also be prepared by liquid or vapor polymerization of olefins in the presence of suitable catalysts, such as boron fluoride, aluminum chloride, ferric chloride, and the like. In general, the Friedel-Crafts catalysts are used. Materials prepared as above may be used as suitable substitutes for linseed oil, tung oil, and the like, in drying oils, enamels, paints, varnishes, core oils, and preservative compositions generally. They may be used to extend, supplement, or add to compositions containing standard vegetable oils without losing any valuable properties of the letter. In some cases our improved materials may serve to improve the quality of compositions of this character because of their synergistic action. They may be used in resin type adhesives, in caulking compounds, factices,-and other materials as mdicated above. They appear to be useful in the manufacture of linoleum to which they impart tough, flexible properties comparable with those of linseed oil. For use in linoleum the carboxylated polymer may be used, in part at least, without esterification.

For some purposes it is desirable to incorporate in our improved composition suitable metalloorganic driers or modifiers, such'as the lead or cobalt naphthenates and abietates. These may be employed in the composition to which our improved polymers are added as ingredients. If desired these modifiers may be mixed directly with the carboxylate polymer and copolymerized therewith to some extent.

It will be understood that other suitable ingredients may be added and/or substituted in our improved composition as understood by' those skilled in the art, without departing from the spirit of this invention.

We claim:

1. A process of preparing synthetic drying oils which comprises condensing ata temperature above 100 C. a polyoleflnic polymer having a molecular weight between 200 and 1000, obtained by the clay treatment of steam cracked gasolines with a compound selected from the group consisting of alpha,beta unsaturated carboxylic acids and alpha,beta unsaturated nitriles and then esterifying the product with an alcohol having from 2 to 20 carbon atoms in a straight chain at a temperature between and 200 C.

2. A process of preparing synthetic drying oils which comprises condensing at a temperature above 100 C. a polyolefinic polymer having a. molecular weight between 200 and 1000, obtained by the clay treatment of steam cracked gasolines with maleic anhydride and then esterifying the prodnot with an alcohol having from 2 to 20 carbon atoms in a straight chain at a temperature between 100 and 200 C.

3. A process of preparing synthetic drying oils which comprises condensing at a temperature above 100 C. a polyolefinic polymer having a molecular weight between 200 and 1000, obtained by the clay treatmentof steam cracked gasolines with a nitrile and then esterifying the product with an alcohol having from 2 to 20 carbon atoms ina straight chain at a temperature between 100 and 200 C.

4. A process of preparing synthetic drying oils which comprises condensing at a temperature above 100 C. a polyolefinic polymer having a molecular weight between 200 and 1000, obtained by the clay treatment of steam cracked gasolines with maleic acid and then esterifying the product with an alcohol having from 2 to 20 carbon atoms in a straight chain at a temperature between 100 and 200 C.

5. A process of preparing synthetic drying oils which comprises condensing at a temperature above 100 C. a polyolefinic polymer having a molecular weight between 200 and 1000, obtained by the clay treatment of steam cracked gasolines with maleic anhydride and then esterifying the product with glycerin at a temperature between 100 and 200 C.

6. A process of preparing synthetic drying oils which comprises condensing at a temperature above 100 C. a polyolefinic polymer having a molecular weight between 200 and 1000, obtained by the clay treatmentof steam cracked gasolines with acrylo mtrile and then esterifying the product with glycerin at a temperature between 100 and 200 C.

7. A process of preparing synthetic drying oils which comprises condensing at a temperature above 100 C. a polyolefinic polymer having a molecular weight between 200 and 1000, obtained by the clay treatmentof steam cracked gasolines with maleic acid and then esterifying the product with glycerin at a temperature between 100 and 200 0.

JOHN C. ZIMMER. JEFFREY H. BAR'I'LE'I'I.

REFERENCES CITED The following references are of record in the file of this patent: 1

UNITED STATES PATENTS, 

1. A PROCESS OF PREPARING SYNTHETIC DRYING OILS WHICH COMPRISES CONDENSING AT A TEMPERATURE ABOVE 100*C. A POLYOLEFINIC POLYMER HAVING A MOLECULAR WEIGHT BETWEEN 200 AND 1000, OBTAINED BY THE CLAY TREATMENT OF STEAM CRACKED GASOLINES WITH A COMPOUND SELECTED FROM THE GROUP CONSISTING OF ALPHA,BETA UNSATURATED CARBOXYLIC ACIDS AND ALPHA.BETA UNSATURATED NITRILES AND THEN ESTERIFYING THE PRODUCT WITH AN ALCOHOL HAVING FROM 2 TO 20 CARBON ATOMS IN A STRAIGHT CHAIN AT A TEMPERATURE BETWEEN 100 AND 200*C. 